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What is meant by rate of a reaction ? Differentiate between average rate and instantaneous rate of a reaction.

Following reactions can occur at cathode during the electrolysis of aqueous silver nitrate solution using Pt electrodes:

In a galvanic cell, the following cell reactions occurs: $\mathbf{Zn}(s)+2\mathbf{A}\mathbf{g}^{+}(\mathbf{a}\mathbf{q})\rightarrow\mathbf{Zn}^{2+}(\mathbf{a}\mathbf{q})+2\mathbf{A}\mathbf{g}(s)$ E°cell = +1.56 V (i) Is the direction of flow of electrons from zinc to silver or silver to zinc? (ii) How will concentration of Zn²⁺ ions and Ag⁺ ions be affected when the cell functions?

(i) Following reactions occur at cathode during the electrolysis of aqueous silver chloride solution : $\mathbf{Ag}^{+}(\mathbf{aq})+\mathbf{e}^{-}\rightarrow\mathbf{Ag}(\mathbf{s})\qquad\qquad\mathbf{E}^{\circ}$ = +0.80 V $\mathrm{H}^{+}(\mathrm{aq})+\mathrm{e}^{-}\rightarrow\frac{1}{2}\mathrm{H}_{2}(\mathrm{g})~~~~~~~~~\mathrm{E}^{\circ}$ = 0.00 V On the basis of their standard reduction electrode potential (E°) values, which reaction is feasible at the cathode and why ? (ii) Define limiting molar conductivity. Why conductivity of an electrolyte solution decreases with the decrease in concentration ?

When a certain conductance cell was filled with 0.1 M KCl, it has a resistance of 85 ohm at 25°C. When the same cell was filled with an aqueous solution of 0.052 M unknown electrolyte, the resistance was 96 ohms. Calculate the molar conductance of the electrolyte at this concentration. [Specific conductance of 0.1 M KCl = 1.29 × 10⁻² ohm⁻¹ cm⁻¹]